Method of securing wrist pins in pistons



Jan. 29 1924.

T. J. LITLE, JR

METHOD OF SECURING WRIST PINS IN PISTONS F iled March 39. 1923 W'WNEISS.

Fig. I

Patented Jan. 29, 1924-.

NETED srATEs 1 1,482,135 arsr THOMAS J. LITLE, JR., OF DETROIT, MICHIGAN, ASSIGNOR T FORD MOTOR COMPANY,

OF DETROIT, MICHIGAN, A CORPORATION OF DELAWARE. H

METHOD OF SECURING WBIST'PINS IN PISTONS.

Application filed M sha, 1923. Serial No. 628,520.

To all whom it may concern: 7

Be it known that I, THOMAS J. Lrrnn, Jr., a citizen of the United States, and residing in the city of Detroit, in the county of l/Vayne and State of Michigan, have invented new and useful Improvements in a Method of Securing Wrist Pins in Pistons,

of which the following is a specification.

The object of my invention is to provide 1 improvements in the method of securing wristpins in pistons, of simple, durable, and

inexpensive construction.

A further object of my invention is to provide means for detachably securing wrist pins in pistons in such a way that the wrist pins. will be very rigidly held in place during the use of the piston in the engine.

A further object of my invention is to provide ametaining device for wrist pins comprising a pin which may be driven thru the wrist pin retaining sleeve for a piston and thru registering openingsin the wrist pin, and to provide retaining means within the hollow wrist pin for holding the pin in place.

A further object of my invention is to provide retaining means for the wrist pin holding device which will. securely lock the hold ing device in place during the use of the piston in a cylinder but which is readily removable when the piston is removed from the cylinder and it is desired, for any reason, to replace the wrist pin. i

With these and other objects in view, my invention consists in the arrangement, com bination and construction of the various parts of my improved device, as described in the specification, claimed in my claims and shown in the accompanying drawings, in which:

Figure 1 shows a side elevation of a piston having the wrist pin therein and my improved wrist pin retaining device installed thereon.

Figure 2 shows a top or plan view of th device shown in Figure 1, and

Figure 3 shows a vertical, sectional view taken on the line 33 of Figure 1.

Referring to the accompanying drawings, I have used the reference numeral 10 to indicate generally a split skirt piston of alumi-' tion is particularly valuable in connection with this type of piston as with these pistons the expansion and contraction of the metal is relatively great at the varying engine temperatures so that a great deal of difficulty has been experienced in securing the Wrist pins into these pistons as the wrist pins are of steel so that the fastening devices which have been in use in connection with the ordinary cast iron pistons would notwork satisfactorily as they permitted play of the piston relative to the wrist pin at cer tain temperatures due to the large difference in the coefiicients of expansion. of these aluminum pistons and the steel wrist pin.

A wrist pin 11 of ordinary construction, that is a hollow or tubular member formed from steel and of cylindrical shape, is inserted thru a hole extending thru the piston 10, to form a pintle or wrist pin to which the connecting rod (not shown) may be connected.

Heretofore considerable difficulty has been experienced in holding this cylindrical wrist pin 11 from rotating in the hole thru the piston as .well as from moving endwise therein as, of course, such movement wears the opening in the comparatively soft metal of the piston so that the wrist pin is allowed movement thereby making the engine noisy and in time causing a possibility of serious damage to the engine.

This wrist pin 11 has an opening 12 therein which registers with corresponding openings in the boss receiving the wrist pin in the piston so that a pin 13 may be driven thru the openings in the boss in the piston 10 and the openings 12 in the wrist pin to thereby hold the wrist pin from longitudinal or rotary movement relative to the piston. This pin 1a has one end tapered, or, perhaps both ends may be tapered, if desired. The central portion forms a driving fit with the openings in the piston boss and the openings in the wrist pin. The pin 14 is further held in place by being driven thru a split sleeve 15 formed of relatively heavy resilient material which is substantially equal in length to the entire diameter of the wrist pin and is designed to embrace the locking pin 14 within the wrist pin to prevent loosening of the wrist pin and accidental displacement thereof. This split resilient sleeve 15 is so designed that it is nor mally of substantially less diameter than the locking pin 14 but sufliciently large so that the tapered end of the pin 14; may be forced thru the sleeve to'expand same when the pin is driven into place. Vhen the pin has been so driven it will be seen that the sleeve 15 will frictionally engage the surface of the locking pin 14: with great force so that the accidental displacement or movement of the locking pin within the piston boss or the wrist pin will. be eliminated.

When it is desired to remove the Wrist pin from the piston the pinlli may be driven out from the sleeve 15 and the wrist pin and piston by 'tapping it with a suitable punch.

Thru an extended experience with the securing of wrist pins in alloy piston I have not as yet found any other method of fastening these wrist' pins which compares in any respect with the method herein disolosed The advantages of this method conslst, gen erally speaking, in an easier assembly and bolts, or the like, while it permits theholes which are drilled thru the piston and Wrist pin to'be exactly the same diameter. This permits the piston maker to eliminate alarge possibility of error in machining together with eliminating the expense of the constructions mentioned. Straight drills such as are necessary for drilling pistons and Wrist pins, are readily held to desired sizes and the locking pin itself may be formed to a desired diameter with comparatively simple and in expensive machine operations. The retainmg sleeve and the taper and the end of the pin need not be held to close limits in connection with their forming, so that the expense of close machine operations in connection'with this job is practically eliminated while the efficiency of the retaining device is remarkable.

Some changes may be made in the arrangement and construction of the various parts of my improved device Without departing from the spirit of the invention therein, and it is my intention to cover by myclaims such changes as may be reasonably included within thevscope thereof.

I claim as my invention: V

1. In a device of the character described, apistonhaving wrist pin receiving bosses therein, one of said bosses having aligned openings therein, a hollow cylindrical Wrist pin designed to be received in said bosses, said'wrist pin having aligned openings adjacent to one end designedto register with the openings in the boss, a split sleeve of resilient material, and a locking pin designed to be driven thru the registering openings and the split sleeve whereby the locking pin and the wrist pin maybe held from movement.

2. In a device of the character described,

a piston having aligned bosses therein designed to receive a wrist pin, a hollowcylindrical wrist pin received Within saidbosses one of said' bosses and the wrist pin having aligned openingstherethru, a locking pin extended thru said openings, and resilient means disposed Within the wrist pin and adapted to co act with the locking pin to hold the latter from movement. V

Means for locking ahollow cylindrical member within another member comprising a pin extended thru the first and second members and a resilient split sleeve normally of' less diameter than the pin designed to engage the pin within the cylindrical member to lock the pin from movement.

- Dated March 12, 1923.

THOMAS J. LrrLE, JR. 

